The fundamental limits
currently faced by traditional computing
devices necessitate the exploration of ways to store, compute, and
transmit information going beyond the current CMOS-based technologies.
Here, we propose a three-dimensional (3D) magnetic interconnector
that exploits geometry-driven automotion of domain walls (DWs), for
the transfer of magnetic information between functional magnetic planes.
By combining state-of-the-art 3D nanoprinting and standard physical
vapor deposition, we prototype 3D helical DW conduits. We observe
the automotion of DWs by imaging their magnetic state under different
field sequences using X-ray microscopy, observing a robust unidirectional
motion of DWs from the bottom to the top of the spirals. From experiments
and micromagnetic simulations, we determine that the large thickness
gradients present in the structure are the main mechanism for 3D DW
automotion. We obtain direct evidence of how this tailorable magnetic
energy gradient is imprinted in the devices, and how it competes with
pinning effects that are due to local changes in the energy landscape.
Our work also predicts how this effect could lead to high DW velocities,
reaching the Walker limit during automotion. This work demonstrates
a possible mechanism for efficient transfer of magnetic information
in three dimensions.